Inhibition of root growth by spermidine is not due to enhanced production of ethylene

Rea, Elvira; Monte, G. Di; Agazio, M. de

doi:10.1016/0168-9452(95)04134-g

Cited by 1 publication

(1 citation statement)

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“…Some authors have already noticed that salt-resistant rice cultivars produce higher amounts of ethylene than salt-sensitive cultivars ( Khan et al , 1987 ; Lutts et al , 1996 ). In classical terrestrial plants, ethylene and PA pathways are considered to be competitive (Muñoz de Rueada et al , 1994; Rea et al , 1995 ). In the present study, leaf segments were excised, and wounding could interfere to some extent with ethylene biosynthesis measurements.…”

Section: Discussionmentioning

confidence: 99%

Putrescine differently influences the effect of salt stress on polyamine metabolism and ethylene synthesis in rice cultivars differing in salt resistance

Quinet

Ndayiragije

Lefèvre

et al. 2010

Journal of Experimental Botany

158

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Effects of salt stress on polyamine metabolism and ethylene production were examined in two rice (Oryza sativa L.) cultivars [I Kong Pao (IKP), salt sensitive; and Pokkali, salt resistant] grown for 5 d and 12 d in nutrient solution in the presence or absence of putrescine (1 mM) and 0, 50, and 100 mM NaCl. The salt-sensitive (IKP) and salt-resistant (Pokkali) cultivars differ not only in their mean levels of putrescine, but also in the physiological functions assumed by this molecule in stressed tissues. Salt stress increased the proportion of conjugated putrescine in salt-resistant Pokkali and decreased it in the salt-sensitive IKP, suggesting a possible protective function in response to NaCl. Activities of the enzymes ornithine decarboxylase (ODC; EC 4.1.1.17) and arginine decarboxylase (ADC; EC 4.1.1.19) involved in putrescine synthesis were higher in salt-resistant Pokkali than in salt-sensitive IKP. Both enzymes were involved in the response to salt stress. Salt stress also increased diamine oxidase (DAO; 1.4.3.6) and polyamine oxidase (PAO EC 1.5.3.11) activities in the roots of salt-resistant Pokkali and in the shoots of salt-sensitive IKP. Gene expression followed by reverse transcription-PCR suggested that putrescine could have a post-translational impact on genes coding for ADC (ADCa) and ODC (ODCa and ODCb) but could induce a transcriptional activation of genes coding for PAO (PAOb) mainly in the shoot of salt-stressed plants. The salt-resistant cultivar Pokkali produced higher amounts of ethylene than the salt-sensitive cultivar IKP, and exogenous putrescine increased ethylene synthesis in both cultivars, suggesting no direct antagonism between polyamine and ethylene pathways in rice.

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Section: Discussionmentioning

confidence: 99%